Rope chains made from precious metals have, for decades, been made largely by hand. The method of making such chains until this very day will now be described in detail with reference to FIGS. 1 to 8. The basic construction element, or component, of such rope chains is a ring formed of a solid or hollow wire, usually of precious metal, e.g. 14 karat gold. A ring 1 shown in FIG. 1 has an opening or gap 2 formed therein. This gap 2 has a narrow dimension 3 at its inner diameter and a wider dimension at its outer diameter.
The solid wire forming the ring (FIG. 2) usually has flattened sides 4 and rounded ends 5 which give the ring 1 a major diameter 6 and a minor diameter 7. The cross-section of the wire forming the ring 1 may also be of generally circular cross-section. The gap 2 of ring 1 is substantially larger than the minor diameter 7 and is slightly larger than the major diameter 6 at its narrowest dimension 3.
A multiplicity of such rings 1 are intertwined to form, in outward appearance, a double helix, as shown in FIG. 3, which is the format for a standard rope chain. These tightly interfitting ring rope chains are hand-made.
For the longest time these chains were made from split annular rings having a 3:1 ratio of ring inner diameter to major wire diameter. U.S. Pat. No. 4,651,517, which is incorporated herein by reference, disclosed that it is possible to produce a rope chain with significant weight savings by using thinner annular split rings having an inner ring diameter slightly more than X times the major wire diameter, where X is an odd number greater than 3. The arrangement of the split rings with respect to one another in building the chain length is the same in this patent as in the previous practice. This arrangement is shown and described in FIGS. 5-7, where X equals 3. The first ring forming the rope chain will be termed the ring "a". It is the first of a series of four rings forming a ring assembly.
The relative orientation of the rings forming the rope chain according to this prior art is important. The ring "a" is initially oriented (manually) so that its gap, designated 20a, lies in a predetermined direction, e.g. facing generally upwardly, as in FIG. 5. The second ring of this assembly, designated as "b" ring, is passed through the gap 20a of the ring "a", with the gap 20b of the ring "b" facing downwardly at about 180.degree. removed from the ring gap 20a of ring a "a", as shown in FIG. 6. The rings "a" and "b" are juxtaposed and intertwined so that they lay against each other, with the periphery of the ring "b" lying against the periphery of the ring "a", to the greatest extent possible, thereby creating a relatively large central opening 30 with the pair of intertwined abutting "a" and "b" rings. The plane of the ring "a" lies in parallel to the plane of the paper, and the plane of the ring "b" is slightly skewed from the a plane.
The gap 20c of "a" third ring "c" is then passed through the gap 20b of the ring "b" and over the minor diameter of the ring "a" and laid angularly against the "a" and "b" rings "a" and "b", the gap 20c of the ring "c" lying in the same orientation as the gap 20a of the ring "a", and as shown in FIG. 7, but with its plane more greatly skewed than the rings "a" and "b". A central opening 30a still remains within the now three intertwined rings "a", "b" and "c". The planes of each of the rings differ from each other by perhaps about 20.degree. because of their angular abutment. In the case where X equals 5, the cross-section of the rings is smaller and the planes of the rings would differ from each other by about 15.degree..
Turning now to FIG. 8, the gap 20d of a fourth ring "d" is now passed over the rings "a", "b" and "c", through the central opening 30b, and thereby envelops the rings "a", "b" and "c" to substantially fill the central opening 30b with rings. The ring "d" is laid against the other rings (a-c) and its plane lies approximately 20.degree. from the plane of the "c" ring. The gap 20d of the ring "d" is disposed in the same orientation as the gap 20b of the ring "b".
The just-described intertwining and orientation of a-d rings permits the continuation of the intertwining of additional assemblies of rings (of four rings each, where X=3, or 6 rings each when X=5 etc.) to create a "double helix" rope chain of a desired length. The adding on of an additional assembly of four rings is a repetition of the orientation previously described with reference to the a-d ring, but the planes of this second assembly lie at approximately 90.degree. to the planes of the respective rings in the first assembly.
It is to be noted that the gaps of the first and third ring additions of a second ring assembly abut the previous first and third rings, and the second and fourth rings pass through the gaps of the previous second and fourth rings and that the relative orientations of the gaps of the rings alternate between adjacent rings about 180.degree.. Thus, as far as the operator is concerned, he or she is always alternating the gap orientation while intertwining each additional ring.
After building up the rings in the manner just described, to form the double helix rope chain (FIGS. 5-8), the rings are held in the desired juxtaposition temporarily by a thin metal wire 25 wrapped about the rings (FIG. 4). Then solder S is intermittently applied, e.g. to every pair of adjacent rings usually at two points of the external periphery thereof. The wire 25 is then removed. The intermittent soldering S results in a rope chain wherein every ring pair is slightly movable, with respect to its adjacent ring pairs, and results in a chain having the desired flexibility for forming a necklace or bracelet.
In my earlier patent application on which U.S. Pat. No. 4,934,135 issued 07/286,657 filed which is incorporated herein by reference, I disclosed that it is possible to prepare high quality rope chains with further additional savings and variability by having X be equal to or greater than 3, said rope chain being formed by a plurality of assemblies of rings in series, each assembly comprising X+1 rings, each ring of said assembly being angularly intertwined with an adjacent ring, each of said assembly of rings comprising at least one ring oriented with its gap turned about 180.degree. with respect to the gap of at least one other ring within said assembly, wherein each assembly of rings comprises at least one group of two or more adjacent rings having their gaps in the same orientation, at least two or more adjacent rings being fixedly attached to each other, each of at least one group of two or more adjacent rings being also fixedly attached to another ring having a gap orientation about 180.degree. with respect to the gaps of the rings of said group of two or more adjacent rings, and the end ring of each assembly in the series envelops the other rings of said assembly.
The above innovative method permits the manufacture of rope chains having variable ring assemblies of both even and odd numbers, i.e. where the ratio of the inner diameter of the ring to its cross-section, X, can be any even or odd number from 3 and above. This is made possible by fixing the similarly oriented adjacent rings to one another, so that each group of such similarly oriented rings can be considered and treated as if it were a single ring with a single gap.
To illustrate this above method of preparing a rope chain, we refer to FIG. 10. Here we see two ring assemblies, "a" to "d" and "aa" to "dd", each having one group of three adjacent rings b-c-d and bb-cc-dd with the same gap orientation and only two rings, "a" and "aa", with gaps oriented 180.degree. with respect of these groups of rings. The rings "d" and "dd" envelop (52, 53) the previous rings of their respective ring assemblies. This arrangement of rings requires that the groups of rings, b-c-d and bb-cc-dd, be soldered at S together to form single units. The last ring "d" and "dd" of each assembly is, in this case, soldered at S.sub.1 to the first ring "aa" and "ee" of the next assembly. In this example, the number of rings which must be manipulated for each assembly and turned 180.degree. with respect to the previous ring is only one, which is a 2/3 saving of time for this type of manipulation. Overall, this arrangement can save approximately 18-20% of labour costs in the manufacture of such a rope chain.